Signs, pictures, displays, and paintings are often illuminated to enhance the display of graphical or visual information to observers, especially in low light conditions. The image may be front lit where the light source is located in front of the image displayed or back lit where the light source is located behind the image that is embedded upon or within media capable of allowing pass-through light emissions. For example, large billboard advertisements often use light boxes with florescent bulbs positioned behind the billboard to illuminate the billboard's image. Some billboards, however, continue to use front lighting where lamps are positioned above or below the billboard and directed toward the billboard's face.
Recently, the evolution of electronic devices such as computers, laptops, cellular telephones, televisions, and the like have stimulated the need and demand for electronic graphical displays such as color liquid crystal displays (LCD). To enhance the observed image, these devices have displays that are typically back lit from a light source. These devices may use waveguides to distribute light uniformly throughout the plane of an image display. Certain devices may also use an edge-lit waveguide wherein a light source is placed in proximity to the edge of a waveguide plate or panel to illuminate the image on the device's display.
Other systems provide back lit illumination for pictures using edge lit waveguides in custom-molded frames.